The report found that ‘inflammation was detected with all nanomaterials’ and that ‘nano-objects consistently have a higher toxicity than non-nano-objects’. However the authors did note that there are ‘considerable differences in the toxicity of different materials’, and that inflammation for the nanomaterials occurred at different dose levels, depending on the type of material. They also found that ‘silver had the highest toxicity’ of the nanomaterials examined.

Noting that ‘sustained inflammation can be seen as one possible early event in the sequence of cancer development’, the authors suggest that ‘nanomaterials can be grouped on [the] basis of their potential to generate inflammation’. As such they propose a preliminary LOEL (Lowest Observable Effect Level) to ‘distinguish the so-called ‘inert’ nanomaterials from nanomaterials with specific toxicity’.